I have a 377 I cant find much difference between the two bedrooms in either model. I removed our memory foam residential from our old camper and put it in the 377 and the only issues is it's weight is going to wear out the gas shocks quickly on the under the bed storage. (I prefer a good nights sleep, I only get in the under bed storage once every two or three trips) Fits like a dream. I moved the mattress and there was 50 lbs of weight difference between Jayco's "Premium" mattress and the Serta. Hope this helps.
Derek, Wife, and 3 kids
2016 NorthPoint 377RLBH
2015 GMC Sierra 3500 DRW SLE Duramax
B & W Companion